1. Field of the Invention
The present invention relates to a method of manufacturing a photoelectric conversion device.
2. Description of the Related Art
Japanese Patent Laid-Open No. 2006-73611 describes a method of manufacturing a solid-state image sensing device, which includes forming the n-type region (charge accumulation region) of a photodiode A1 by ion implantation. More specifically, a gate oxide film 102 and a polysilicon film 103 are sequentially formed on an n-type silicon substrate 101. A first photoresist pattern 105 is formed on the polysilicon film 103. Using the first photoresist pattern 105 as a mask, the gate oxide film 102 and the polysilicon film 103 are etched to expose the n-type silicon substrate 101, thereby forming a gate electrode pattern. Next, a second photoresist pattern 106 is formed without removing the first photoresist pattern 105. Ion implantation is performed using the second photoresist pattern 106 as a mask, thereby forming an n-type region 107 of the photodiode A1 in the well of the n-type silicon substrate 101.
Japanese Patent Laid-Open No. 2006-73611 describes forming the n-type region (charge accumulation region) 107 of the photodiode A1 by performing ion implantation while exposing a surface region of the semiconductor substrate where the photodiode A1 should be formed. However, when ion implantation is done while exposing the region to form the photodiode A1, damage or metal contamination occurs due to the ion implantation.
On the other hand, Japanese Patent Laid-Open No. 2006-73611 makes no disclosure about surface region formation in the photoelectric converter by ion implantation through an insulating film that covers the surface of the semiconductor substrate. There is no disclosure about how to suppress a variation in the implantation profile of the surface region in the photoelectric converter upon ion implantation through the insulating film, either.